/**
 * @title PullToRefreshListView.java
 * @package com.esun.cheetah.view.custom
 * @description 下拉刷新控件
 * @author liugan修改自网络开源代码
 * @date 2012-3-31
 * @copyright 无
 */
package com.esun.cheetah.view.custom;

import com.esun.cheetah.R;
import com.esun.util.log.EDebug;
import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ProgressBar;
import android.widget.TextView;

/**
 * @title PullToRefreshListView
 * @description 下拉刷新ListView
 * @author liugan
 */
public class PullToRefreshListView extends ListView implements OnScrollListener {

	private static final String TAG = "listview";
	

	/**
	 * @description 列表的内部状态
	 */
	private final static int RELEASE_To_REFRESH = 0;// 释放时刷新
	private final static int PULL_To_REFRESH = 1;// 下拉可以刷新
	private final static int REFRESHING = 2;// 正在刷新
	private final static int DONE = 3;// 操作完成
	private final static int LOADING = 4;

	// 实际的padding的距离与界面上偏移距离的比例
	private final static int RATIO = 3;

	private LayoutInflater inflater;

	// listView的头部视图
	private LinearLayout headView;

	private TextView tipsTextview;// 显示状态提示
	private TextView lastUpdatedTextView;// 显示最后刷新时间
	private ImageView arrowImageView;// 显示箭头
	private ProgressBar progressBar;// 显示进度条

	/**
	 * @description 箭头翻转的动画
	 */
	private RotateAnimation animation;
	private RotateAnimation reverseAnimation;

	// 用于保证startY的值在一个完整的touch事件中只被记录一次
	private boolean isRecored;

	private int headContentWidth;
	private int headContentHeight;

	/**
	 * @field startY
	 * @description 一次下拉操作开始时点击点的Y轴坐标
	 */
	private int startY;

	/**
	 * @field firstItemIndex
	 * @description ListView的第一个可见Item
	 */
	private int firstItemIndex;

	/**
	 * @field state
	 * @description 列表的内部状态
	 */
	private int state;

	/**
	 * @field isBack
	 * @description 用来标识是否是从RELEASE_To_REFRESH 向上滑到 PULL_To_REFRESH 这个状态，此时箭头要翻转
	 */
	private boolean isBack;

	private OnRefreshListener refreshListener;

	/**
	 * @field isRefreshable
	 * @description 设置了OnRefreshListener 监听器后可刷新
	 */
	private boolean isRefreshable;

	public PullToRefreshListView(Context context) {
		super(context);
		init(context);
	}

	public PullToRefreshListView(Context context, AttributeSet attrs) {
		super(context, attrs);
		init(context);

		// 通过反射修改fastScroller的图标
		// try {
		// Field f = AbsListView.class.getDeclaredField("mFastScroller");
		// f.setAccessible(true);
		// Object o=f.get(this);
		// f=f.getType().getDeclaredField("mThumbDrawable");
		// f.setAccessible(true);
		// Drawable drawable=(Drawable) f.get(o);
		// drawable=getResources().getDrawable(R.drawable.icon);
		// f.set(o,drawable);
		// } catch (Exception e) {
		// throw new RuntimeException(e);
		// }
	}

	private void init(Context context) {
		setCacheColorHint(context.getResources().getColor(R.color.transparent));
		inflater = LayoutInflater.from(context);

		headView = (LinearLayout) inflater.inflate(
				R.layout.pull_to_refresh_head, null);

		arrowImageView = (ImageView) headView
				.findViewById(R.id.head_arrowImageView);
		arrowImageView.setMinimumWidth(70);
		arrowImageView.setMinimumHeight(50);
		progressBar = (ProgressBar) headView
				.findViewById(R.id.head_progressBar);
		tipsTextview = (TextView) headView.findViewById(R.id.head_tipsTextView);
		lastUpdatedTextView = (TextView) headView
				.findViewById(R.id.head_lastUpdatedTextView);

		measureView(headView);
		headContentHeight = headView.getMeasuredHeight();
		headContentWidth = headView.getMeasuredWidth();

		headView.setPadding(0, -1 * headContentHeight, 0, 0);
		headView.invalidate();

		EDebug.o("size", "width:" + headContentWidth + " height:"
				+ headContentHeight);

		addHeaderView(headView, null, false);
		setOnScrollListener(this);

		animation = new RotateAnimation(0, -180,
				RotateAnimation.RELATIVE_TO_SELF, 0.5f,
				RotateAnimation.RELATIVE_TO_SELF, 0.5f);
		animation.setInterpolator(new LinearInterpolator());
		animation.setDuration(250);
		animation.setFillAfter(true);

		reverseAnimation = new RotateAnimation(-180, 0,
				RotateAnimation.RELATIVE_TO_SELF, 0.5f,
				RotateAnimation.RELATIVE_TO_SELF, 0.5f);
		reverseAnimation.setInterpolator(new LinearInterpolator());
		reverseAnimation.setDuration(200);
		reverseAnimation.setFillAfter(true);

		state = DONE;
		isRefreshable = false;
	}

	/**
	 * @description 屏幕上出现新的可见Item时会触发该事件，此时记录下屏幕上方第一个可见Item
	 */
	public void onScroll(AbsListView arg0, int firstVisiableItem, int arg2,
			int arg3) {
		firstItemIndex = firstVisiableItem;
	}

	public void onScrollStateChanged(AbsListView arg0, int arg1) {
	}

	public boolean onTouchEvent(MotionEvent event) {

		if (isRefreshable) {
			switch (event.getAction()) {
			// 按下事件，需记录按下点的Y坐标
			case MotionEvent.ACTION_DOWN:
				// 当第一个可见Item是头部视图并且该事件还未被记录时
				if (firstItemIndex == 0 && !isRecored) {
					isRecored = true;
					// 保存该点的Y坐标值
					startY = (int) event.getY();
					EDebug.o(TAG, "在down时候记录当前位置‘");
				}
				break;

			// 手指离开事件，需要根据当前状态做响应
			case MotionEvent.ACTION_UP:
			case MotionEvent.ACTION_CANCEL:
				//
				if (state != REFRESHING && state != LOADING) {
					if (state == DONE) {
						// 什么都不做
					}
					if (state == PULL_To_REFRESH) {
						state = DONE;
						changeHeaderViewByState();

						EDebug.o(TAG, "由下拉刷新状态，到done状态");
					}
					if (state == RELEASE_To_REFRESH) {
						state = REFRESHING;
						changeHeaderViewByState();
						onRefresh(true);

						EDebug.o(TAG, "由松开刷新状态，到done状态");
					}
				}

				isRecored = false;
				isBack = false;

				break;

			case MotionEvent.ACTION_MOVE:
				int tempY = (int) event.getY();

				if (!isRecored && firstItemIndex == 0) {
					EDebug.o(TAG, "在move时候记录下位置");
					isRecored = true;
					startY = tempY;
				}

				if (state != REFRESHING && isRecored && state != LOADING) {

					// 保证在设置padding的过程中，当前的位置一直是在head，否则如果当列表超出屏幕的话，当在上推的时候，列表会同时进行滚动

					// 可以松手去刷新了
					if (state == RELEASE_To_REFRESH) {

						setSelection(0);

						// 往上推了，推到了屏幕足够掩盖head的程度，但是还没有推到全部掩盖的地步
						if (((tempY - startY) / RATIO < headContentHeight)
								&& (tempY - startY) > 0) {
							state = PULL_To_REFRESH;
							changeHeaderViewByState();

							EDebug.o(TAG, "由松开刷新状态转变到下拉刷新状态");
						}
						// 一下子推到顶了
						else if (tempY - startY <= 0) {
							state = DONE;
							changeHeaderViewByState();

							EDebug.o(TAG, "由松开刷新状态转变到done状态");
						}
						// 往下拉了，或者还没有上推到屏幕顶部掩盖head的地步
						else {
							// 不用进行特别的操作，只用更新paddingTop的值就行了
						}
					}
					// 还没有到达显示松开刷新的时候,DONE或者是PULL_To_REFRESH状态
					if (state == PULL_To_REFRESH) {

						setSelection(0);

						// 下拉到可以进入RELEASE_TO_REFRESH的状态
						if ((tempY - startY) / RATIO >= headContentHeight) {
							state = RELEASE_To_REFRESH;
							isBack = true;
							changeHeaderViewByState();

							EDebug.o(TAG, "由done或者下拉刷新状态转变到松开刷新");
						}
						// 上推到顶了
						else if (tempY - startY <= 0) {
							state = DONE;
							changeHeaderViewByState();

							EDebug.o(TAG, "由DOne或者下拉刷新状态转变到done状态");
						}
					}

					// done状态下
					if (state == DONE) {
						if (tempY - startY > 0) {
							state = PULL_To_REFRESH;
							changeHeaderViewByState();
						}
					}

					// 更新headView的size
					if (state == PULL_To_REFRESH) {
						headView.setPadding(0, -1 * headContentHeight
								+ (tempY - startY) / RATIO, 0, 0);

					}

					// 更新headView的paddingTop
					if (state == RELEASE_To_REFRESH) {
						headView.setPadding(0, (tempY - startY) / RATIO
								- headContentHeight, 0, 0);
					}

				}

				break;
			}
		}

		return super.onTouchEvent(event);
	}

	/**
	 * @title changeHeaderViewByState
	 * @description 当状态改变时候，调用该方法，以更新界面
	 */
	private void changeHeaderViewByState() {
		switch (state) {
		// 状态变为’ 释放后刷新 ‘时
		case RELEASE_To_REFRESH:
			arrowImageView.setVisibility(View.VISIBLE);
			progressBar.setVisibility(View.GONE);
			tipsTextview.setVisibility(View.VISIBLE);
			lastUpdatedTextView.setVisibility(View.VISIBLE);

			arrowImageView.clearAnimation();
			arrowImageView.startAnimation(animation);

			tipsTextview.setText("松开刷新");

			EDebug.o(TAG, "当前状态，松开刷新");
			break;
		// 状态变为’ 下拉可刷新 ‘时
		case PULL_To_REFRESH:
			progressBar.setVisibility(View.GONE);
			tipsTextview.setVisibility(View.VISIBLE);
			lastUpdatedTextView.setVisibility(View.VISIBLE);
			arrowImageView.clearAnimation();
			arrowImageView.setVisibility(View.VISIBLE);
			// 是由RELEASE_To_REFRESH状态转变来的，需要翻转箭头
			if (isBack) {
				isBack = false;
				arrowImageView.clearAnimation();
				arrowImageView.startAnimation(reverseAnimation);
			}
			tipsTextview.setText("下拉刷新");
			EDebug.o(TAG, "当前状态，下拉刷新");
			break;
		// 状态变为’ 正在刷新 ‘时
		case REFRESHING:

			headView.setPadding(0, 0, 0, 0);

			progressBar.setVisibility(View.VISIBLE);
			arrowImageView.clearAnimation();
			arrowImageView.setVisibility(View.GONE);
			tipsTextview.setText("正在刷新...");
			lastUpdatedTextView.setVisibility(View.VISIBLE);

			EDebug.o(TAG, "当前状态,正在刷新...");
			break;
		// 状态变为’ 动作已完成 ‘时
		case DONE:
			reset();
			break;
		}
	}

	/**
	 * @title setOnRefreshListener
	 * @description 设置监听器
	 * @param refreshListener
	 */
	public void setOnRefreshListener(OnRefreshListener refreshListener) {
		this.refreshListener = refreshListener;
		isRefreshable = true;
	}

	/**
	 * @title OnRefreshListener
	 * @description 刷新状态的监听器
	 * @author liugan
	 */
	public interface OnRefreshListener {
		public void onRefresh(boolean bUpdate);
	}

	/**
	 * @title onRefreshComplete
	 * @description 刷新完成后，由外部调用
	 */
	public void onRefreshComplete() {
		state = DONE;
		// Date date = new Date();
		// lastUpdatedTextView.setText("更新于: " + format.format(date));
		changeHeaderViewByState();
	}

	/**
	 * @title onRefresh
	 * @description 刷新时，回调监听器的onRefresh()方法
	 */
	private void onRefresh(boolean bUpdate) {
		if (refreshListener != null) {
			refreshListener.onRefresh(bUpdate);
		}
	}

	/**
	 * @title measureView
	 * @description 测量头部视图的宽和高 ，具体步骤不理解
	 * @param view
	 */
	private void measureView(View view) {
		// 获得View的布局参数，Layout_width和layout_height
		ViewGroup.LayoutParams p = view.getLayoutParams();
		// 如果没有的话就设置为FILL_PARENT，和WRAP_CONTENT
		if (p == null) {
			p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
					ViewGroup.LayoutParams.WRAP_CONTENT);
		}
		int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width);
		int childHeightSpec;
		if (p.height > 0) {
			childHeightSpec = MeasureSpec.makeMeasureSpec(p.height,
					MeasureSpec.EXACTLY);
		} else {
			childHeightSpec = MeasureSpec.makeMeasureSpec(0,
					MeasureSpec.UNSPECIFIED);
		}
		view.measure(childWidthSpec, childHeightSpec);
	}

	public void setAdapter(BaseAdapter adapter) {
		// Date date = new Date();
		// lastUpdatedTextView.setText("更新于: " + format.format(date));
		super.setAdapter(adapter);
	}

	/**
	 * @title updateRefresh
	 * @description 外部其他方式刷新则调用此方法
	 */
	public void updateRefresh() {
		if (state == DONE) {
			headView.setPadding(0, 0, 0, 0);

			progressBar.setVisibility(View.VISIBLE);
			arrowImageView.clearAnimation();
			arrowImageView.setVisibility(View.GONE);
			tipsTextview.setText("加载中...");
			lastUpdatedTextView.setVisibility(View.VISIBLE);
			state = REFRESHING;
			onRefresh(false);
		}
	}

	/**
	 * @title autoRefresh
	 * @description 外部其他方式刷新则调用此方法
	 */
	public void autoRefresh() {
		if (state == DONE) {
			headView.setPadding(0, 0, 0, 0);

			progressBar.setVisibility(View.VISIBLE);
			arrowImageView.clearAnimation();
			arrowImageView.setVisibility(View.GONE);
			tipsTextview.setText("正在刷新...");
			lastUpdatedTextView.setVisibility(View.VISIBLE);
			state = REFRESHING;
			onRefresh(true);
		}
	}

	public void setUpdateTime(String time){
		lastUpdatedTextView.setText("更新于："+time);
	}
	
	/**
	 * @title reset
	 * @description 将类别状态重置
	 */
	public void reset() {
		headView.setPadding(0, -1 * headContentHeight, 0, 0);
		state = DONE;
		progressBar.setVisibility(View.GONE);
		arrowImageView.clearAnimation();
		arrowImageView.setImageResource(R.drawable.arrow);
		tipsTextview.setText("下拉刷新");
		//lastUpdatedTextView.setVisibility(View.VISIBLE);
	}

}
